Royal Society EL/W3/3

Copy of a letter from Christopher Wren to Lord Brouncker

Entered LB.1.97
Dr Christopher Wrens letter to the Lord Brounker President of the Royal Society About Experiments for his Majesty's Reception

My lord

The Act and Noise of Oxford being over I retired to myselfe as speedily as I could to obey your Lordship and contribute something to the Collection of Experiments designed by the Society for his Majesty's reception. I concluded on something, I thought most sutable to such an occasion, but the stupidity of our Artists here makes the Apparatus so tedious that I foresee, I shall not be able to bring it to anything ere I am necessitated to take a journey, which I am unavoidably tyed to. What in the meane while to suggest to your Lordship I cannot guesse: the solemnity of the occasion and my sollicitude for the Honor of the Society make me think nothing proper, nothing remarkable enough. It is not every yeare will produce such a master Experiment as the Torricellean, and so fruitfull as that is of New Experiments, and therefore the Society hath deservedly spent much time upon it, and its offspring: and if you have any notable Experiment, that may appeare to open new light into principles of Philosophy, nothing would better become the pretensions of the Society, though possibly such would be too jejune for this purpose, in which there ought to be something of pompe: on the other side, to produce knacks only and things to rayse wonder, such as Kercher, Scotby and even Juglers abount with, will scarce become the gravity of the occasion. It must therefore be something between both, Luciferous in Philosophy, and yet whose use and advantage is obvious without a Lecture, and besides it may surprise with some unexpected effect, and be commensurable for the ingenuity of the contrivance. Halfe a dozen of Experiments thus qualified will be abundantly enough for an houres Entertainment, and I cannot believe, the Society can want them, if they look back in their own store. For myselfe I must professe freely, I have not anything by me, sutable to the idea I have of what ought to be performed upon this occasion. Geometricall problems, and new lines, new methods (how usefull soever) will be but tastelesse in a transient shew. New Theories or Observations, or Astronomicall Instruments (either for Observation or facilitation of the Calculus) are valuable to such Artists only, who have particularly experimented the defects, that those things pretend to supply. Sciographicall knacks (of which 100 varieties may yet be given) are so easy in the Invention, that now they are cheape. Scenographicall, Catopticall and Diopticall Tricks require excellent painting, as well as Geometricall Truth in the profile, or else they deceive not. Designs of Engines for ease of labour, or promoting any thing in Agriculture, or the Mechanick Trades, I have occasionally thought upon divers, but they are not intelligible without letters and references, and often not without something of Demonstration. Designes in Architecture are only considerable, as they are appropriated to some work in hand, or else they are a kind of Criticismes and search into Antiquity. In Navigation twill be presumption to proffer at anything, while we expect from your Lordship an accurate Theory from the time of Noah unknowne, and reserved for your Lordship a 2d great endeavour of humane nature. The Needle had possibly more of Chance than invention, yet it gave us a new world, this will be the product of reason and philosophy, and may give us the remaining undiscovered parts of the Globe. In the few Chymicall Experiments I have been acquainted with, I cannot tell, whether there be any, that will not prove too durty or tedious for an Entertainment. Experiments in Anatomy (though of the most value for their use) are sordid and noysome to any, but those, whose desire of knowledge persuadeth them to digest them. Experiments for the establishment of natural philosophy are seldom pompous: tis upon Billiards and Tennis bals, upon the parting of Sticks and Topps, upon a Viall of water, or a wedge of Glasse, that the great Descartes hath built the most refined accurate theoryes that human wit ever reacht to, and certainly Nature in the best of her works is apparent enough by obvious things, were they but curiously observed. The key, that opens treasures, is often plain and rusty, but, unlesse it be guilt, the key alone will make no show at Court.

If I have been conversant in philosophicall things, it hath been principally in those wayes, which I have recounted to your Lordship, by which your Lordship perceiveth, how uselesse I am for this occasion, yet if your Lordship will still pursue me, I know not what shift to make, but to retire back to something, I have formerly produced or discoursed of.

I have pleased myself not a little with the play of the weather wheale (the only true way to measure expansions of the Aire) and I fancy, it must needs give others satisfaction, if it were once finely made, which I suppose may be done, if the Circular pipe, which cannot be truly blown in glasse, were made of Bras, by those who make Trumpets and Sackbuts (who wiredraw their Pipes through a hole and equall them, and then filling them with melted Lead, turne them round into what flex they please) but the insides of the Pipe must be vernished with China-Vernice (which Greatrix hath) to preserve it from the quicksilver, and the Glasses must be fixed to the Pipe with Vernice, which I take to be the best Cement in the world for thus the Chinese fixe Glasse and mother of Pearle in their workes.

It would be no unpleasing spectacle to see a man live without new Aire, as long as you please. A description of the vessel for cooling and percolating the Aire at once I formerly shewed the Society, and left with Mr Boyle. I suppose it worth putting in practise. You will at least learne thus much from it, if something else in Aire is requisite for life then that it should be coole only, and free from the fulginous vapours and moisture, it was infected with in exspiration, for all these will in probability be separated in the circulation of the breath in the Engine. If Nitrous fumes be found requisite (as I suspect) wayes may perhaps be found to supply that too, by placing some benigne Chymicall Spirits, that by fumes may impregnate the Aire within the vessell.

If an artificial eye were truly and dioptrically made (which I would have at least 3 inches diameter) it would represent the picture, as nature paints it. The Cornea and Chystalline must be glas, the other humors water. I once surveighed an horses eye as exactly as I could, measuring what the diameters of the severall spheres of the Humors were, and what the proportions of the distances of the centers of every sphericall superficies was upon the Axis of the Eye. The wayes, by which I did it, are too long to rehearse; but the projection in treble the magnitude Sir P. Neile may possibly find; or, if your Lordship think it worthwhile, I shall reiterate the Experiment.

A Needle, that would play in a Coach, will be as usefull to know the Coast and way (Joyned with the way-wiser) as a pleasant diversion to the Travailer, and would be an acceptable present to his Majesty, who might thus, as it were, sayle by land. The Fabrick of it may be such as this: In a sphere of Glasse of 2 inches diameter, half full of water, cause a short broad heavy needle to swim, being boyed up by the Chart, and both varnished: instead of a Cap and Pin, let the perforated needle play about a smal wire or horse haire, extended like a perpendicular Axis in the Glas-sphere; which being made weighty with Lead, fixed to the Nadir, and a Horizon as it were cemented to it, let it play in circles, like the vulgar compasse. Then let a Hemisphericall Concave-box, containing the sphere in its circles be hung upon springs after this manner. Suppose a basis, upon which are erected perpendicularly 3. stiffe woodden springs of yew; from the Ends of which springs are strings or nerves strained, forming an equilateral triangle, the midle of whose sides passe through 3. small loopes on the brim of the Concave, which therefore hanging on the Lutestrings represents a circle inscribed in a Triangle: from the midle of the basis ariseth a worme spring fastned by a spring to the Nadir of the Concave, drawing it down a litle, and acting against the other 3. springs. Thus I suppose the springs will take much of the laterall and perpendicular concussions; the circles will take of Oscillations; the Agitations remaining will be spent in the water, and stilled by the Chart covering the superficie of the water; for thus we see a Trencher swimming in a bucket keep the water from spilling in carriage. And the Chinese instead of Circles have their compas swimming in water. Lastly, I would have at the bottom of the basis near the edge made like a brush, but with soft thick and inclining bristles, which will ease it like 1000. springs. It should be placed on the midle of the floore of the Coach, where by opening a window you may likewise see the waywiser placed on the pearch.

My Lord, if my first designs had been perfect, I had not troubled your Lordship with so much scrible, but with something performed and done, but being taken of by my occasions, I had rather be impertinent than disobedient, and am fain in this letter to do like the common Chymist, who, when projection (his fugitive darling) hath left him thredbare, is fain to fall to vulgar preparations to pay his debts. And I must needs acknowledg, I am not only indebted to the Society and most particularly to your Lordship, to whom I ow a double duty, both as to our President and to my very good Lord and Patron.

O.B.C. July:30:1663